This research program uses a unique set of methods to study the influence of intrapartum analgesic administration on infant behavioral development in a suitable animal model, the rhesus monkey. For the proposed research, this model will be expanded by including methods for epidural drug administration during labor, assessment of plasma protein drug binding patterns, and induction of intrapartum hypoxia. Problems to be addressed are: (1) the infant behavioral effects of epidural analgesia/anesthesia (bupivacaine and meperidine); (2) the influence of differential fetal-maternal protein binding on fetal drug exposure; (3) the interaction of narcotic analgesics with intrapartum hypoxia. In addition, we will continue characterization of the endogenous opiate system in the perinatal period to aid in understanding the effects of opiate analgesics. Finally, some parallel studies will be conducted in guinea pigs to extend the capability for investigation of these research problems to a more accessible and economical animal model. Basic research in animal models can provide both the conceptual and empirical framework for continued advances in development of safe and effective obstetric analgesia practices.